The statements in this section merely provide background information related to the present disclosure and may or may not constitute prior art.
A continuously variable transmission (“CVT”) typically includes a belt and pulley system that operatively couples a rotary power source, such as an engine or electric motor, to a double gear final drive unit. The belt and pulley system generally includes first and second pairs of pulley cones having a torque transmitting belt or chain extending between the cone pairs. Each pulley cone pair includes an axially stationary pulley member and an axially movable pulley member. Each movable pulley member is axially adjustable with respect to the stationary pulley member by a hydraulic system. The hydraulic system provides primary and secondary hydraulic pressures to the respective movable pulley members to adjust the running radius of the first and second pulley cone pairs which in turn controls the output/input ratio of the continuously variable transmission. Movement of the cones steplessly or continuously varies the ratio of an input speed to an output speed. With the continuously variable transmission, small but effective ratio changes can be attained. This is in contrast to a fixed gear ratio unit where any ratio changes are step values.
CVT axial length and mass significantly impact its power density and efficiency. Known CVTs include four (4) rotational axes, which typically include a first axis rotatably supporting a first movable pulley set, a second axis rotatably supporting a second movable pulley set, a third axis for an intermediate member such as a transfer shaft, and a fourth axis defining an output axle or rotational output member. Each axis of rotation requires independent sets of bearing members, increasing mass and costs, and the four axes configuration extends both an axial length and a lateral width of the CVT. Accordingly, there is a constant need for improved CVT designs that minimize axial length, width, and mass while providing sufficient performance characteristics.